Field of the Invention and Relates Art Statement
This invention relates to an electronic endoscope apparatus wherein a picture image displayed in a monitor is positioned on the basis of an output signal of a solid state imaging device.
An electronic endoscope using a solid state imaging device, such as a CCD, for an imaging means has recently come to be used. Such an electronic endoscope contains a solid state imaging device in the tip part of an insertable part or is fitted with a television camera containing a solid state imaging device in an optical endoscope (such as, for example, a fiber scope).
In the latter, an optical image transmitted by an image guide within the fiber scope is formed on the imaging surface of the solid state imaging device by an image forming lens system within the television camera. However, the optical axis (on the exit end side of the image guide) of the fiber scope and the optical axis of the image forming lens system on the television camera side will be displayed from each other when fitted.
When the above mentioned displacement is produced, the center position of the picture image displayed on the monitor picture surface will be displaced from a predetermined position to be displayed and also from the center position of the image guide.
In order to eliminate such a displacement, the image forming lens system has conventionally been mechanically adjusted.
Particularly, in a vein fiber scope in which the image guide is fine, the optical axis adjustment with the solid state imaging device is required to be precise and the mechanical adjustment has been difficult. Also, it has been difficult to mechanically correct the displacement of the optical axes. Therefore, in a monitor observation, the image of an object will be displaced from a predetermined position.
When an endoscope picture image is to be displayed as large as possible on a monitor picture surface, if the displaying position is displaced, the displayed picture image will be partly missing.
Also, when the picture image displayed on the monitor picture surface is to be photographed, if the displaying position is displaced, the photographed picture image may be partly missing.